Actuator

ABSTRACT

An actuator includes an electromagnetic coil arrangement that is movable relative to a magnetic field generator; between a first position and a second position of the actuator. The actuator is arranged such that, when the actuator is in the first position, a pulse of current through the electromagnetic coil arrangement produces a region of magnetic field that repels the magnetic field generator from the first position and attracts the magnetic field generator towards the second position to move the actuator to the second position.

REFERENCE TO RELATED APPLICATION

This application claims priority to PCT Application PCT/GB02/002825filed on Jun. 19, 2002.

BACKGROUND OF THE INVENTION

The present invention relates generally to actuators, and in particularto actuators for use in vehicles.

Electric motors are used as actuators for moving components. Theelectric motors include armature windings and stator windings. Thearmature is designed to be in a close running fit within the stator tomaximize the magnetic field effect.

Linear solenoids are also used as actuators. A current is passed throughan electromagnetic coil, which creates a magnetic field to eitherattract or repulse a magnetic core of the linear solenoid.

As known, the magnetic effect decreases with distance. Therefore, mostlinear solenoids are designed with as small an air gap as possible. Itis also known that linear solenoids can only operate over relativelyshort distances.

SUMMARY OF THE INVENTION

An object of the present invention is to provide an improved actuator.

The present invention provides an actuator including an electromagneticcoil arrangement that is movable relative to a magnetic field generatorbetween a first position and a second position of the actuator. Theactuator is arranged such that, with the actuator in the first position,a pulse of current through the electromagnetic coil arrangement producesa region of magnetic field that repels the magnetic field generator fromthe first position and attracts the magnetic field generator towards thesecond position to move the actuator to the second position.

Preferably, the electromagnetic coil arrangement includes a singleelectromagnetic coil.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will now be described, by way of example only, withreference to the accompanying drawings in which;

FIGS. 1 and 2 show a first embodiment of an actuator according to thepresent invention in a first position and a second position;

FIGS. 3 and 4 show a second embodiment of the actuator according to thepresent invention in a first position and a second position;

FIG. 3A shows an end view of a coil of FIG. 3;

FIG. 4A shows the results of tests carried out on the actuator of FIG.3;

FIGS. 5 and 6 show a third embodiment of the actuator according to thepresent invention in a first position and a second position;

FIG. 7 shows a schematic view of the actuator according to the presentinvention used to provide for block locking;

FIGS. 8 and 9 show a schematic view of the actuator according to thepresent invention used to provide for free-wheel locking;

FIG. 10 shows a schematic view of the actuator according to the presentinvention used to provide for power unlatching;

FIGS. 11 and 12 show a schematic view of the actuator according to thepresent invention used to provide for power latching;

FIG. 13 shows a valve incorporating the actuator according to thepresent invention;

FIGS. 14 and 15 show a schematic view of a relay incorporating theactuator according to the present invention.

FIG. 16 is a view of a latch arrangement according to another form ofthe present invention;

FIG. 16A is an enlarged view of part of FIG. 16;

FIG. 16B is a view similar to FIG. 16A with a magnetic pawl in adifferent position;

FIG. 17 shows the latch arrangement of FIG. 16 partially through anopening operation in an unlocked but latched position;

FIG. 18 shows the latch arrangement of FIG. 16 at the end of an openingoperation in an unlatch condition;

FIG. 19 shows the latch arrangement of FIG. 16 wherein an attempt hasbeen made to open the latch while in a locked condition;

FIGS. 20, 20A, 20B, 20C and 20B show an embodiment of a latcharrangement according to another form of the present invention;

FIG. 21 is a view of a latch arrangement according to another form ofthe present invention in an unlocked latched first condition;

FIG. 22 is a view of the latch arrangement of FIG. 21 partially througha first actuation of the release mechanism;

FIG. 23 is a view of the latch arrangement of FIG. 21 having completedthe first actuation;

FIG. 24 is a view of the latch arrangement of FIG. 21 with the releasemechanism having been released and with the latch in a latched secondcondition;

FIG. 25 is a view of the latch arrangement of FIG. 21 shown in areleased position, having been mechanically released;

FIG. 26 is a view of the latch arrangement of FIG. 21 shown in areleased position having been released by a power actuator;

FIG. 27 is a view of the latch arrangement of FIG. 21 shown in a lockedcondition;

FIG. 28 is a view of the latch arrangement of FIG. 21 shown in anunlatched condition with the release handle in a rest position;

FIG. 29 is a view of various components of the latch arrangement of FIG.21 shown in isolation for clarity;

FIG. 30 is a view of the claw of the latch arrangement of FIG. 21 shownin isolation;

FIG. 31 is a view of a further embodiment of the present invention;

FIGS. 32 to 28 are views corresponding to FIG. 21 to 27, respectively,of a further embodiment of a latch arrangement according to the presentinvention;

FIG. 39 is a view of the embodiment of the latch arrangement of FIG. 32shown in a locked condition with the outside handle pulled; and

FIG. 40 is a close up view of part of the latch arrangement of FIG. 21A.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

FIGS. 1 and 2 show an actuator 10 having an actuator chassis 12 (onlyshown in FIG. 1 for clarity) upon which an electromagnetic coil assembly14 is fixedly mounted on.

The electromagnetic coil assembly 14 includes coil windings 16 connectedto power leads 18 and 20. The coil windings 16 form a cylinder withinwhich a core 22 of magnetic material, such as iron, is positioned. Thecore 22 acts to concentrate the magnetic flux lines.

Passing a current in one direction through the coil winding 16 via thepower leads 18 and 20 creates a south pole and a north pole, asindicated in FIG. 1. Reversing the direction of current will reverse theposition of the north pole and the south pole.

FIG. 1 also shows a magnetic field generator in the form of a toggle 24including a mounting portion 26 that is pivotally mounted via a pivot Pto the actuator chassis 12. A permanent magnet 28 is secured to an endof the mounting portion 26 that is remote from pivot P. A permanentmagnet 28 includes a north pole N1 and a south pole S1.

Operation of the actuator 10 is as follows. When no current is flowingthrough the coil windings 16, the end 22A of the core 22 is magneticallyneutral, i.e., it is neither a north pole nor a south pole. As shown inFIG. 1, the north pole N1 of the permanent magnet 28 is closer to theend 22A than the south pole S1. As such, the predominant magneticattraction is between the end 22A and the north pole N1, and the toggle24 remains in a position as shown in FIG. 1.

In order to move the toggle 24 from the position shown in FIG. 1 to aposition shown in FIG. 2, current is fed through the core windings 16 toproduce a north pole at the end 22A, thus repelling the north pole N1 ofthe permanent magnet 28 and causing the toggle 24 to pivot clockwisearound the pivot P.

As the north pole N 1 moves away from the end 22A, the south pole S1progressively approaches the end 22A and is therefore progressivelyattracted to the north pole at the end 22A, further driving the toggle24 in a clockwise direction until it reaches the position as shown inFIG. 2.

Once in the position shown in FIG. 2, the end 22A again becomesmagnetically neutral when the electric current flowing through the coilwinding 16 stops, although the toggle 24 remains in the position asshown in FIG. 2 because of the greater magnetic attraction between thesouth pole S1 and the end 22A.

The toggle 24 can be moved back to the position as shown in FIG. 1 byreversing the current to provide a south pole at the end 22A.

The movement of the toggle 24 is as a result of two sets of forces,namely: a) repulsion force between two similar magnetic poles and b) anattraction force between opposite magnetic poles.

The repulsive force between two similar poles decreases with thedistance between the poles. Also, the attractive force between twoopposite poles increases as the opposite poles approach each other.

As the pole moves from the position shown in FIG. 1 to the positionshown in FIG. 2 and as the repulsive forces between the north pole N1and the north pole at the end 22A progressively decrease, the attractiveforces between the south pole S1 and the north pole at the end 22Aprogressively increase. This provides for a more uniform force acrossthe range of movement. This can be contrasted with known devices, suchas solenoids, wherein either similar poles are used to repel each otheror opposite poles are used to attract each other during movement. At notime during the use of known solenoids is an attraction force ofopposite poles used in conjunction with repelling forces of similarpoles.

Preferably, stops 13A and 13B are provided to limit the rotation of thetoggle 24 in a clockwise and counter-clockwise direction, respectively.

FIGS. 3 and 4 show a further embodiment of an actuator 110, withcomponents similar to those of the actuator 10 being labelled 100greater.

In this case, the electromagnetic coil assembly 114 includes a frame130, which is connected to an end 122B of a core 122 and passes outsidecoil windings 116.

An end 130A of the frame 130 is positioned at the same end of the coilwindings 116, but is spaced from the end 122A. The frame 130 is made ofa magnetic material, such as iron or steel, and acts to concentrate themagnetic flux lines, i.e., it acts as a conduit for the magnetic fluxlines.

In particular, with reference to FIG. 3A, the end 130A does notcompletely encircle the coil windings 116, but is positioned only on oneside of the coil windings 116 in a sector.

When current is fed to the coil windings 116 in one direction, a southmagnetic pole is generated at the end 122A of the core 122. Because ofthe frame 130, the north pole that would normally be expected to beproduced at the end 122B is transferred to the end 130A of the frame130. In particular, the core 122 and the frame 130 concentrate themagnetic flux lines. However, there is an “air gap” between the ends130A and 122A that the magnetic flux has to jump. The magnetic fluxlines in the air gap are shown as lines 132.

It can be seen, especially from FIG. 3A, that the magnetic flux lines132 are concentrated in a sector of the coil winding 116 as they passfrom the end 130A to the end 122A.

Consideration of the toggle 124 shows that the permanent north pole N2and the permanent south pole S2 are situated at opposite ends of thetoggle 124 on either side of a pivot P2, with the north pole N2 beingsituated proximate to the electromagnetic coil.

Operation of the actuator 110 is as follows. Current is fed through thecoil windings 116 to produce a north pole at the end 130A and a southpole at the end 122A. This causes the permanent north pole N2 to berepelled from the north pole at the end 130A and simultaneouslyattracted towards the south pole at the end 122A, thus causing thetoggle 124 to pivot clockwise to the position shown in FIG. 4.

The toggle 124 can be moved back to the position shown in FIG. 3 byreversing the current through the coil winding 116 such that a northpole is provided at the end 122A and a south pole is provided at the end130A.

Experiments were carried out on a sample actuator 110 to optimize theposition of the toggle 124 relative to the electromagnetic coil assembly114. Thus, the position of a pivot P1 was adjusted to vary a gap G. Avoltage was applied across power leads 118 and 120 and was increaseduntil the toggle 124 moved from one position to the other position. Theresults are shown in FIG. 4A and surprisingly, with a small gap G of 0.5mm, approximately 7 volts was required to move the toggle 124. However,as the air gap progressively increased, a lower voltage was required toactuate the device. Thus, with an air gap of 1.0 mm, approximately 4.5volts was required, and with an air gap of 1.5 mm, approximately 3.5volts was required.

This was a surprising result since it is generally accepted thatmagnetic devices operate best, and hence require lower power, with smallair gaps.

This is best understood by considering the fact that magnetic fluxcannot easily turn through sharp corners. Thus, FIG. 3 shows that themagnetic flux lines 132 pass in an arc between the end 130A and the end122A. Where the magnetic flux lines 132 cross the flux lines emitted bythe permanent magnet, the toggle 124 will easily move. However, when thegap is too small, it is harder to move the toggle 124 since the magneticflux lines 132 pass through the permanent magnet rather than across themagnetic field.

In a further embodiment, the single electromagnetic coil assembly 114could be replaced by a pair of electromagnetic coils positioned adjacentone another and wired in series such that the north pole N2 can besimultaneously repelled from a north pole of one magnetic coil andattracted to a south pole of the adjacent magnetic coil.

FIG. 5 shows a further embodiment of an actuator 210, which includes anelectromagnetic coil assembly 214 fitted to a chassis (not shown) of theactuator 210. A yoke 240 is made of a non-magnetic material, such as aplastics material. A first permanent magnet 242 is mounted in an end240A of the yoke 240, and a second permanent magnet 244 is mounted in anend 240B of the yoke 240.

A south pole S3 of the permanent magnet 242 faces a south pole S4 of apermanent magnet 244. The coil assembly 214 is situated between thesouth poles S3 and S4. The yoke 240 and the permanent magnets 242 and244 are moveable via sliders (not shown) between the positions shown inFIG. 5 and FIG. 6. Starting at the position shown in FIG. 5, a currentis passed through the coil assembly 214 in a first direction, and anorth pole is created at the end 222A of the core, and a south pole iscreated at the end 222B, causing the yoke 240 to move to the position asshown in FIG. 6.

Reversing the current through the coil assembly 214 will reverse themagnetic poles, causing the yoke 240 to move back to the position asshown in FIG. 5. The ends 22A and 22B act as stops to limit the downwardand upward movement of the yolk 240.

The actuators of the present invention can be used in many fields, inparticular on vehicles such as cars and to provide security functions.It is therefore preferable that they are capable of functioning on carswhich have a “12 volt” system. Thus, preferably the actuators can beused with an operating voltage of 14 volts (alternator output voltage),12 volts (battery voltage) or 8 volts (partially drained battery).Similarly, where the actuators are used on vehicles with a “24 volt”system, it is preferable for them to operate at 28 volts, 24 volts and16 volts, respectively. Where the actuators are used on vehicles with a“42 volt” system, it is preferable for them to operate at 49 volts, 42volts and 28 volts, respectively.

In all embodiments described so far, the electromagnetic coil assemblyis fixed relative to the chassis of the actuator, and the magnetic fieldgenerator (permanent magnet) is caused to move. Preferably, this allowsthe power leads to the electromagnetic coil assembly to remainstationary. However, in further embodiments and under certaininstallations, it may be preferable for the permanent magnets to remainstationary and to allow the electromagnetic coil assembly to move.

Furthermore, the magnetic field generator has thus far only been shownto include a permanent magnet. In further embodiments, the permanentmagnet could be replaced by a further electromagnetic coil.

In further embodiments, the electromagnetic coil assembly 214 could bereplaced by a permanent magnet, and the permanent magnets 242 and 244can be replaced by electromagnetic coils wired in series such that oneof the electromagnetic coils is attracted towards the adjacent magnet,while the other of the electromagnetic coils is repelled from theadjacent magnet.

FIG. 7 shows a schematic view of a latch arrangement 50 including a doorhandle 51 connected to a door latch 52 via a rod 53. The door handle 51is actuated by pivoting it about pivot a P4 to cause the rod 53 to moveto the left and unlatch the latch 52, allowing an associated door (notshown) to be opened.

The rod 53 carries an abutment 54 situated proximate to a furtherabutment 55 mounted on the door. An actuator 56 according to the presentinvention carries an actuator abutment 57 which, by operation of theactuator, can be inserted into a space between the abutments 55 and 54,thus preventing unlatching of the latch 52 by blocking movement of therod 53 and hence locking the door. The actuator 56 can be operated towithdraw the actuator abutment 57 to the position shown in dottedoutline, thus allowing the abutment 54 to move to the left uponoperation of the door handle 51, thus unlocking the door. In a furtherpreferred embodiment, the actuator 56 and associated components requiredfor locking can be situated within a latch housing of the latch 52.

FIGS. 8 and 9 show a schematic view of a “free wheel” type of lockingsystem situated within a latch housing 66. Operation of a door handle 60causes a lever 61 to pivot counter-clockwise about a pivot P5, causing aslider 62 to move to the right and push a pawl lifter 63 to the right,thus releasing the latch 52.

The slider 62 is slidingly mounted on a toggle 64 of an actuator 65according to the present invention. The toggle 64 pivots about a pivotP6. Actuation of the actuator 65 causes the toggle 64 to move to theposition as shown in FIG. 9 such that actuation of the inside doorhandle 60 moves the lever 61 such that it bypasses the slider 62 anddoes not cause release of the latch 52. FIG. 8 shows the system in anunlocked condition, and FIG. 9 shows the system in a locked condition.

Where the handle 51 or 60 is an inside handle, the system provides for achild safety and/or superlocking (or deadlocking) function inconjunction with a lockable outside handle.

FIG. 10 shows a door latch 70 including a rotating latch bolt in theform of a claw 71. A striker 72 can be retained in the position as shownin FIG. 10 by virtue of a toggle 73 that acts as a claw pawl against aclaw abutment 74. Actuation of an actuator 75 according to the presentinvention causes the toggle 73 to rotate counter-clockwise about a pivotP7, thus releasing the claw 71 which can then rotate counter-clockwiseto allow the striker 72 to be withdrawn from a claw mouth 76. Stops canbe provided to limit the clockwise and counter-clockwise rotation of thetoggle 73. In particular, an edge 71A of the claw 71 can be used tolimit clockwise rotation of the toggle 73.

FIGS. 11 and 12 show a latch arrangement as described in the applicant'searlier granted Great Britain patent number GB2328242. The Great Britainpatent provides a full explanation of the operation of a latch 80.However, in summary, the latch 80 is a power latching latch, i.e., alatch in which an actuator 81 moves a lever 82 in a counter-clockwisedirection such that a pawl 83 engages in a notch 84 of a claw 85,driving the claw 85 to the position as shown in FIG. 12 when the doorhas been closed and the latch is in the position shown in FIG. 11. Inthis case, the actuator 81 is an actuator according to the presentinvention.

The actuator of the present invention may also be used to open a fuelfiller flap by mounting the flap (not shown) to the toggle 24 and 124.Alternatively, the actuator may be used to unlatch a flap that isresiliently biased towards an open position, for example.

FIG. 13 shows a valve 90 having an inlet 91 and alternate outlets 92 and93. The toggle 94 sits within a valve body 95 and selectively blocks theoutlet 92 or outlet 93. As shown in FIG. 13, liquid or gas pumpedthrough inlet 91 will exit via the outlet 93. Actuation of the actuator96 will cause the toggle 94 to rotate counter-clockwise, blocking theoutlet 93 and opening the outlet 92. The portions of the valve body 95act as stops to limit the clockwise and counter-clockwise rotation ofthe toggle 94.

FIGS. 14 and 15 show a relay 97 having an actuator 97A according to thepresent invention that is attached to a relay contact 98. A furtherrelay contact 98A is mounted on the body of the relay 97, and the relaycontact 98 can be opened or closed by actuation of the actuator 97A.

There now follows a description of an embodiment of an actuatoraccording to the present invention used as part of a latch arrangement.The present invention can be used in latch arrangements, and inparticular latch arrangements for use within doors of cars(automobiles).

Known car doors include latches for releasably retaining the car door ina closed position. Such latches can be locked when the car is leftunattended or even when an occupant is in the vehicle to prevent accessto the vehicle by unauthorized people.

These latches can be moved between a locked condition and an unlockedcondition either by manual means, such as by operating an inside sillbutton or an exterior key barrel, or can be powered between the lockedcondition and the unlocked condition by a power actuator which can becontrolled remotely by, for example, infrared devices.

A problem with power locking/unlocking is that it may not be possible tochange the state of the lock in the event of a power loss e.g., during aroad traffic accident or because of a flat battery. Thus, where avehicle is in use, the doors are locked and the vehicle is involved in aroad traffic accident, the occupant of the vehicle may be locked in thevehicle immediately following the crash, which clearly has safetyimplications. Furthermore the power actuator is expensive to produce andmanufacture.

Thus, in one form of the invention, latch arrangement includes a latch,a release mechanism, a manually actuable element and a control meansincluding an actuator. The latch is operable to releasably retain astriker in use. The release mechanism is capable of being moved by themanually actuable element from a rest position through an unlockedposition to a release position wherein it unlatches the latch. Thecontrol means has a locked condition at which actuation of the manuallyactuable element does not cause unlatching of the latch and an unlockedcondition at which the release mechanism achieves the unlocked positionduring an initial movement of the manually actuable element. Duringsubsequent movement of the manually actuable element, the releasemechanism achieves the unlatch position.

Preferably, movement of a door handle provides two functions: namelyunlocking the latch mechanism and releasing the latch mechanism.Furthermore, the control means can be configured to ensure the latcharrangement remains in a locked condition independent of actuation ofany door handles (inside or outside doors) when necessary.

Preferably, the release mechanism includes a release link having anabutment operable to move a latch release element. Preferably, when thecontrol means is in the locked position, actuation of the manuallyactuable element moves the abutment, but the abutment does not move thelatch release element. Preferably, the abutment is mis-aligned with therelease element in the rest condition. Preferably, the release link isoperably movable by a release lever.

Preferably, a part of the release mechanism is retained in a restposition by the control means to provide for the lock condition.Preferably, the part of the release mechanism is retained by magneticattraction or by a control pawl. Preferably, the part of the releasemechanism is a lock/unlock lever which is retained in a first positionwhen the control means is in a locked condition and is allowed to moveto a second position when the control means is in an unlocked condition.

Preferably, the lock/unlock lever is connected to the release link by aconnector. Preferably, the lock/unlock lever, the connector and therelease link substantially move in unison during the initial movement ofthe manually actuable element. Preferably, the lock/unlock lever, theconnector and the release link rotate about a pivot during the initialmovement. Preferably, the pivot mounts the lock/unlock lever on achassis of the latch arrangement.

Preferably, the lock/unlock lever remains stationary during subsequentmovement of the manually actuable element. Preferably, the releasemechanism is designed to return to the rest position from the releaseposition upon release of the manually actuable element.

Preferably, the release mechanism is biased to the rest position by aresilient member. Preferably, a first resilient member biases therelease mechanism to the unlocked position from the released position,and a second resilient member biases the release mechanism to the restposition from the unlock position. Preferably, the latch is furthermovable between a latched position and a released position by a poweredreleased actuator. Preferably, the control means is movable between thelocked condition and the unlocked condition by manual operation of acoded security device, such as a key.

The figures show a latch arrangement 410 having a latch 412 (only partof which is shown), a release mechanism 416, a powered control means(actuator) 418, a manually actuable elements in the form of an insidehandle 420 and an outside handle 421.

The latch 412 is mounted on a car door and is operable to releasablyretain a striker mounted on fixed structure of the car, such as a B postor a C post. The latch 412 typically might include a latch bolt in theform of a rotating claw which engages the striker. To ensure the clawretains the striker, a pawl can be provided to retain the latch bolt ina closed position. The pawl includes a latch release element in the formof a pawl pin 414. [00098] With the pawl pin 414 in a position A asshown in FIG. 16, closing of the door causes the rotating claw to engagethe striker, and the pawl will then retain the striker in the closedposition. Movement of the pawl pin 414 to the position B, as shown inFIG. 16, will release the pawl from engagement with the claw, thusallowing the striker to be released from the claw and allowing the doorto open. Thus, with the pawl pin 414 in the position A of FIG. 16, thelatch 412 can be latched to the striker, and with the pawl pin 414 inthe position B of FIG. 16, the latch 412 can be unlatched from thestriker.

The release mechanism includes a release lever 426, a release link 428,a connector link 430 and a lock/unlock lever 432. The release lever 426is pivotally mounted about a pivot C on a chassis 424 of the latcharrangement 410. One end 426A of release lever 426 is connected via alinkage 434 (shown schematically) to a manually actuable element in theform of the inside handle 420.

The end 426A is further connected by a further linkage 435 (shownschematically) to a further manually actuable element in the form of theoutside door handle 421. Operation of either the handle 420 or 421causes the release lever 426 to rotate clockwise about the pivot C. Theend 426B of the release lever 426 is connected via a pivot D to the end428A of the release link 428. The end 428B of the release link 428includes an abutment 422 for engagement with the pawl pin 414, as willbe further described below.

The release link 428 is connected to an end 430A of the connector link430 by a pivot E which is positioned between the ends 428A and 428B. Theend 430B of the connector 430 is connected to an end of the arm 432A ofthe lock/unlock lever 432 by a pivot F.

The lock/unlock lever 432 further includes arm 432B having a pin 437 andan arm 432C having abutment 438 and 439. The lock/unlock lever 432 ispivotally mounted about a pivot G onto the chassis 424.

The lock/unlock lever 432 is made from mild steel, and in particular theabutment 438 is made from a ferromagnetic material. However, in furtherembodiments other materials can be used (see below).

The actuator according to the present invention is provided in the formof the powered control means 418 which includes an electromagnet 442 anda magnetic pawl (toggle) 444.

The electromagnet 442 is mounted on the chassis 424 and includeswindings 446, a core 448 and electric leads 450 and 451. A pawl stop 452is provided on one side of the electromagnet 442 and is made of magneticmaterial (such as iron or steel) and thus acts as part of a frame, oneend of which is connected to the core 448.

The magnetic pawl 444 includes a permanent magnet and is pivotallymounted about a pivot H onto the chassis 424. The end 444A of themagnetic pawl 444 includes abutments 454, 456 and 458, which will befurther described below.

A tension spring 460 is connected to the chassis 424 and the releaselever 426 and acts to bias the release lever 426 in a counter-clockwisedirection when viewing FIG. 16. A further tension spring 462 (only shownin FIG. 18 for clarity) biases the pin 437 and the pivot D together.

In further embodiments, different forms of springs can be used, inparticular torsion springs (clock springs) in place of tension springs460 and 462, to perform the same biasing action. The lock/unlock leverstop 464 is mounted on the chassis 424.

As a result of the tension spring 462, the end 428A of the release link428 is biased into engagement with the pin 437. In further embodiments,the end of the release lever 426 could engage the pin 437, as could apart of the pivot D.

The magnetic pawl 444 has a south pole at an end 444B and a north poleat an end 444A. Applying DC current to the windings 446 via the electricleads 450 and 451 in a first direction will create a magnetic fieldaround the electromagnet which will bias the north pole in the end 444Aof the magnetic pawl 444 to the left when viewing FIG. 1 i.e.,counter-clockwise about the pivot H until the abutment 454 engages thepawl stop 452.

Applying DC current in a second direction to the windings 446 via theelectric leads 450 and 451 will cause a different magnetic field to formaround the electromagnet such that the north pole end 444A of themagnetic pawl 444 is biased to the right when viewing FIG. 1 i.e.,clockwise around the pivot H until the abutment 456 engages the end 433of the arm 432C of the lock/unlock lever 432 (see FIG. 16B). Under theseconditions, the abutment 458 is opposite the abutment 439 and willprevent rotation of the lock/unlock lever 432 counter-clockwise aboutthe pivot G (see below).

To move the magnetic pawl 444 between the positions shown in FIGS. 16Aand 16B, it is only necessary to apply a short pulse (e. g., 50 ms) ofcurrent to the windings 446 in the appropriate direction, since undernormal circumstances once the magnetic pawl 444 has achieved one of thepositions as shown in FIGS. 16A or 16B, there are no forces which tendto move the magnetic pawl 444 out of those positions.

In a preferred embodiment, the center of gravity of the magnetic pawl444 is substantially located at the pivot H since, in the event of aroad traffic accident, the arrangement will not tend to rotate themagnetic pawl 444 because of acceleration or deceleration occurringduring the accident.

In a further preferred embodiment, a relatively light detent maintainsthe magnetic pawl 444 in either of the positions as shown in FIG. 16Aand FIG. 16B, which can nevertheless be overcome by manual operation ofa key or by pulsing the electromagnet.

Counter-clockwise rotation of the lock/unlock lever 432 about the pivotG can be prevented by applying and maintaining DC current in the firstdirection to the windings 446 since the abutment 438 is made from aferromagnetic material and will therefore be magnetically attracted toelectromagnet 442.

The powered control means 418 has three conditions. In a firstcondition, no power is applied to the windings 446, and the magneticpawl 444 is in the position as shown in FIG. 16B. In a second condition,power is supplied and maintained in a first direction to the windings446, thus attracting the abutment 438 and ensuring that the magneticpawl 444 is positioned as shown in FIGS. 16 and 16A. In a thirdcondition, no power is supplied to the windings 446 and the magneticpawl 444 is in position as shown in FIG. 16, and the permanent Northmagnetic pole is attracted to the magnetic material of the pawl stop452.

Operation of the latch arrangement is as follows. With the poweredcontrol means 418 in the third condition, the door can be manuallyopened as follows. As mentioned previously, with the powered controlmeans 418 in the third condition, the magnetic pawl 444 is positioned asshown in FIG. 16 and thus does not restrict rotation of the lock/unlocklever 432 in a counter-clockwise direction.

Furthermore, no power is supplied to the windings 446, and thus theelectromagnet 442 also does not restrict movement of the lock/unlocklever 432 in a counter-clockwise direction.

Initial movement of either the inside handle 420 or the outside handle421 moves the release lever 426 in a clockwise direction about the pivotC to the unlocked position, as shown in FIG. 17.

The lock/unlock lever 432 has rotated counter-clockwise about the pivotG to a position where the arm 432A abuts the lock/unlock lever stop 464.The abutment 438 has become disengaged from the electromagnet 442.

FIG. 17 shows that the end 428A of the release link 428 has remained incontact with the pin 437. Thus, the connector link 430 and the releaselink 428 have also substantially rotated about the pivot G. As shown inFIG. 17, the abutment 422 aligns with the pawl pin 414. This can becontrasted with the position of the abutment 422, as shown in FIG. 16,where it is not aligned with the pawl pin 414.

Further movement of the inside door handle 420 or the outside doorhandle 421 moves the release lever 426 from the position as shown inFIG. 17 to the position as shown in FIG. 18.

In view of the fact that the arm 432A of the lock/unlock lever 432 is inabutting engagement with the lock/unlock lever stop 464, the lock/unlocklever 432 cannot rotate further in a counter-clockwise direction. Thus,the connector link 430 rotates counter-clockwise about the pivot Frelative to the lock/unlock lever 432. The abutment 422 of release link428 moves into engagement with the pawl pin 414 and moves it fromposition A as shown in FIG. 17 to position B as shown in FIG. 18. Aspreviously mentioned, movement of the pawl pin 414 from the position Ato the position B unlocks the latch.

When the inside door handle 420 and the outside door handle 421 arereleased, the spring 460 and the spring 462 return the release mechanism416 and the pawl pin 414 to the position as shown in FIG. 16.

While the movement of the inside door handle 420 or the outside doorhandle 421, and hence movement of the release lever 426, has beendescribed in two stages, such two stage movement is not discernible by aperson operating the door handles 420 and 421. Furthermore, themechanism is designed to move seamlessly from the position as shown inFIG. 18 to the position as shown in FIG. 16.

With the control means in the second condition i.e., DC current suppliedto the windings 446 in the first direction and the magnetic pawl 444 isin a position as shown in FIG. 16, the lock/unlock lever 432 ismaintained in the position as shown in FIG. 16 by magnetic attraction.

Thus, operation of the inside door handle 420 or the outside door handle421 will cause the release lever 426 to rotate in a clockwise directionas shown in FIG. 16, which will result in the end 428A of the releaselink 428 from immediately disengaging the pin 437 such that the releaselever 426, the release link 428 and the connector link 430 move to theposition as shown in FIG. 19.

While the abutment 422 is moved, such movement causes the abutment 422to bypass the pawl pin 414 and to not impart any movement to the pawlpin 414 in view of the fact that it was initially mis-aligned with thepawl pin 414. Thus, while the inside door handle 421 or the outside doorhandle 420 has been moved, the door has not become unlatched. In furtherembodiments, it is possible to arrange an abutment (such as the abutment422) to be permanently aligned with a latch release element (such as thepawl pin 414 but remote therefrom) such that with the latch arrangement410 in a locked condition, the abutment 422 approaches the pawl pin 414but does not move it. With the latch arrangement 410 in an unlockedcondition, the abutment 422 approaches, engages and then moves the pawlpin 414.

With the control means in the second condition, the door latch remainsin a locked condition.

With the control means in the first condition i.e., where no power isprovided to the windings 446 but the magnetic pawl 444 is in a positionas shown in FIG. 1B, counter-clockwise rotation of the lock/unlock lever432 is again prevented, though this time by cooperation of the abutments439 and 458. Thus, actuation of the inside door handle 421 or theoutside door handle 420 will again cause the release lever 426, therelease link 428 and the connector link 430 to move to the position asshown in FIG. 19.

FIG. 17 shows schematically a power actuator P which is independentlyoperable to release the latch.

Further shown schematically is a coded security device 470 in the formof an externally mounted key barrel into which a key can be inserted.Actuation of the key barrel via the key is capable of moving themagnetic pawl 444 between the positions shown in FIG. 16A and 16B.

The latch arrangement is configured such that when the associatedvehicle is in use, the control means is set to the second conditioni.e., power is maintained to the windings 446. Under such circumstances,electric power lost to resistance in the windings 46 can be compensatedfor by the fact that the engine of the vehicle is running and hence thebattery recharging system (such as an alternator) can recharge thebattery to ensure it does not go flat.

When the vehicle is parked and left unattended, the control means can beset to the first condition to lock the latch. The control system doesnot drain the vehicle battery in the first condition.

The control mechanism can also be set to the third condition when thevehicle is parked and is required to be in an unlocked condition. In thethird condition, there is no drain on the battery.

The control means can be changed between the first condition and thethird condition by applying a pulse of electrical power to the windings446 in an appropriate direction.

With the vehicle in use and the control means in the second condition,as mentioned above, the lock/unlock lever 432 is maintained in theposition as shown in FIG. 16 by feeding power to the electromagnet. Inthe event of a power failure, such as might occur following a roadtraffic accident, the control means will by definition change to thethird condition and hence the doors will become unlocked and occupantsof the vehicle will be able to escape from the vehicle.

With the vehicle parked and with the control means in the firstcondition i.e., with the vehicle locked, pulsing of the electromagnet tomove the control means from the first condition and the third conditionto unlock the vehicle will not be possible in the event that the vehiclebattery is flattened, perhaps as a result of an interior light beingleft on. However, it is nevertheless possible to manually unlock thevehicle by use of the key and the key barrel 470. The key and the keybarrel 470 can also be used to lock the vehicle, if necessary.

Power is continually fed to the windings 446 only when the vehicle is inuse. When the vehicle is parked, power is only momentarily fed to thewindings 446 to change between the locked condition and the unlockedcondition.

This arrangement significantly reduces the chance of flattening thebattery when the vehicle is parked, but still allows the doors to beopened in the event of a power loss following a road traffic accident.

The electromagnet 442 needs to only be strong enough to retain thelock/unlock lever 432 in the position shown in FIG. 16 when theelectromagnet 442 is in the second condition i.e., when power is beingsupplied to the electromagnet 442. Thus, the electromagnet 442 has to bestrong enough to overcome the forces in tension spring 460 duringinitial movement of the inside handle 421 or the outside handle 420, andit has to overcome the forces in tension spring 460 and 462 during asubsequent movement of the inside handle 421 or the outside handle 420.The electromagnet 442 is not required to be strong enough to move thelock/unlock lever 432 from the position as shown in FIG. 17 to aposition such that the abutment 438 engages the electromagnet 442.

The powered control means 418 has two ways of preventing rotation of thelock/unlock lever 432, namely by permanently energizing of the windings446 or by moving the magnetic pawl 444 to the position as shown in FIG.16B. In further embodiments, in particular when no power release P isprovided, the control means can be used to simply lock and unlock thevehicle e.g., when parked. As such, it is only necessary for thewindings 446 to be pulsed to move the magnetic between the positions asshown in FIG. 16A and FIG. 16B. As such, the electromagnet 442 is notrequired to attract the lock/unlock lever 432, which can therefore bemade of a non ferromagnetic material, such as a plastics material. Underthese circumstances, it is necessary to have a manual override systemoperable by the inside handle 421 (but not the outside handle 420) suchthat when the inside handle 421 is moved, the magnetic pawl 444, if inthe position as shown in FIG. 16B, is moved to the position as shown inFIG. 16A. Once the magnetic pawl 444 is in the position as shown in FIG.16A, the latch release mechanism 416 can then operate in its two stagemanner i.e., aligning the abutment 422 with the magnetic pawl 444followed by moving the magnetic pawl 444 from position A to position B,as shown in FIG. 16, to open the latch. Under such an arrangement, it ispreferable that the release mechanism 416 fully returns to the restposition upon release of the inside handle 421 i.e., the abutment 422becomes mis-aligned with the pawl pin 414.

There now follows a description of an embodiment of an actuatoraccording to the present invention used as part of a latch arrangement,and in particular latch arrangements used within doors of cars.

The invention provides a latch arrangement including a latch, a manuallyactuable element, a release mechanism and a power control meansincluding an actuator. The latch is operable to releasably retain astriker in use, and the release mechanism is capable of being moved bythe manually actuable element from a latched position to an unlatchedposition wherein it unlatches the latch. The power control means has afirst condition, a second condition and a third condition.

With the power control means in the first condition, the control meansis in a non-powered condition and actuation of the manually actuableelement does not cause the release mechanism to unlatch the latch. Withthe power control means in the second condition, the powered controlmeans is in a powered condition and actuation of the manually actuableelement does not cause the release mechanism to unlatch the latch. Withthe power control means in the third condition, the power control meansis in a non-powered condition and actuation of the manually actuableelement causes the release mechanism to unlatch the latch.

Preferably, a part of the release mechanism is retained in a lockedposition by the control means to provide for a lock condition of thelatch. Preferably, the part of the release mechanism is retained bymagnetic attractionor by a pawl. Preferably, the part of the releasemechanism is a lock/unlock lever which is retained in the first positionby the control means to provide for the lock condition and is allowed tomove to a second position to provide for the unlocked condition.

Preferably, the control means includes an electromagnet to retain thepart of the release mechanism in the unlocked position. Preferably, theelectromagnet is incapable of moving the part of the release mechanismfrom the unlocked position to the locked position. Preferably, thecontrol means includes a magnetic pawl movable between a locked positionand an unlocked position. Preferably, the electromagnet is pulsed tomove the pawl between the locked position and the unlocked position.Preferably, the pawl is pivotally movable, and the center of gravity ofthe pawl is substantially at the axis of the pivot.

Preferably, the release mechanism is designed to return to the restposition from the release position upon release of the manually actuableelement. Preferably, the release mechanism is biased to the restposition by a resilient member.

Preferably, a first resilient member biases the release mechanism to theunlocked position from the released position, and a second resilientmember biases the release mechanism to the rest position from the unlockposition.

Preferably, unlatching of the latch arrangement causes the releasemechanism to move to a locked condition. Preferably, the releasemechanism can be retained in the locked condition while the latch is inthe unlatched condition. Preferably, the release mechanism is retainedin the locked condition by putting the control means into the firstcondition. Preferably, the release mechanism is retained in the lockedcondition by putting the control means into the second condition.

Preferably, the latch is further movable between a latched position anda released position by a powered released actuator. Preferably, thecontrol means is movable between the locked condition and the unlockedconditions by manual operation of a coded security device, such as akey.

FIGS. 20, 20A, 20B, 20C and 20D show a further embodiment of a latcharrangement 310 having components which fulfill substantially the samefunction as those components in the latch arrangement labelled 300greater. Again, the actuator according to the present invention isprovided in the form of a powered control means 318. A pawl stop 352 isprovided on one side of an electromagnet 342 and is made of a magneticmaterial (such as iron or steel) and thus acts as part of a frame, oneend of which is connected to a core 348.

Further shown is a latch bolt in the form of a rotating claw 1 pivotablymounted about a pivot W, which is retained in the position shown in FIG.20 by a pawl 2 that is pivotably mounted about a pivot X. A striker 3can be retained in the position as shown in FIG. 20 to latch a door in aclosed position. In this case, the claw 1 includes a cam lug 4 on theouter periphery thereof which engages a lug 5 of a lock/unlock lever332, as will be further described below. In this case, there is furtherincluded an abutment 390 which limits counter-clockwise rotation of arelease lever 326.

FIG. 20A shows the latch arrangement 310 in an unlocked conditionwherein the release lever 326 abuts an abutment 390, a lock/unlock lever332 abuts an abutment 364, and an end 328A of a release link 328 abuts apin 337, with an abutment 338 being remote from the electromagnet 342.In this position, the abutment 338 aligns with a pawl pin 314. Note thatthe position of components shown in FIG. 20A is equivalent to theposition of similar components as shown in FIG. 17.

FIG. 20B shows the latch arrangement 310 in a locked condition whereelectrical power is fed to the windings 346 to maintain the abutment 338in engagement with the electromagnet 342. The release lever 326 stillengages the abutment 390, while the lock/unlock lever 332 no longerengages the abutment 364 and the end 328A of the release link 328 nolonger engages the pin 337. The abutment 338 is now mis-aligned with thepawl pin 314. Thus, pivotal movement of the release lever 326 in aclockwise direction will cause the abutment 338 to bypass the pawl pin314, and thus the door will remain closed.

Consideration of FIG. 20A shows that in the event that the release lever326 is pivoted in a clockwise direction to disengage with the abutment390, the release lever 326, the release link 328, and the connector 330will move to the position as shown in FIG. 20C, resulting in theabutment 322 engaging and moving the pawl pin 314 to position B, asshown in FIG. 20C, thus allowing the door the to open.

The latch arrangement 310 only momentarily achieves the position asshown in FIG. 20C because once in this position, the claw 1 rotatescounter-clockwise about a pivot W. This simultaneously releases thestriker 3 from the mouth of the claw 1 and also causes the cam lug 4 tocontact the lug 5, thus driving the lock/unlock lever 332 to theposition as shown in FIG. 20D. This in turn allows the pawl pin 314 toreturn to the position A and causes the connector 330 and the releaselink 328 to adopt the position as shown in FIG. 20D.

As shown in FIG. 20D, the release lever 326 is disengaged from theabutment 390 i.e., an inside door handle or an outside door handle isstill in an actuated position. With the inside door handle or theoutside door handle in the actuated position, the door latch can then belocked either by supplying and maintaining power to the windings 346, bypulsing the windings 346 such that the pawl 344 moves clockwise to aposition equivalent to that shown in FIG. 16B, or by manual operation ofthe key again moving the pawl 344. Subsequent release of the inside doorhandle or the outside door handle will either return the latcharrangement 310 to the position as shown in FIG. 20B (when power issupplied and maintained to the windings 346) or to the position as shownin FIG. 20B, except with the pawl 2 moved across.

Alternatively, where no power is supplied to the windings 346, thenneither the electromagnet 342 nor the pawl 344 will restrict rotationalmovement of the lock/unlock lever 332 which will return to the positionas shown in FIG. 20C upon release of the inside door handle or theoutside door handle.

The electromagnet 342 is therefore only required to hold thelock/unlocked lever 332 in the locked position, as shown in FIG. 20, andis not required to return it to the position from the unlocked positionsince this is carried out by cooperation between the cam lug 4 and thelug 5.

In an alternative embodiment, it is possible to provide an electromagnet342 which is sufficiently powerful to move the lock/unlock lever 332from the position as shown in FIG. 20A to the position as shown in FIG.20B to be able to lock the door without having to open the door.

There now follows a description of another embodiment of an actuatoraccording to the present invention used as part of a latch arrangement.The present invention can be used in the latch arrangement, and inparticular a latch arrangement for land vehicles, such as cars.

Known door latches need to keep the associated vehicle door in a closedposition in the event of a road accident. Under such circumstances, theclosed vehicle door contributes significantly to the strength of thepassenger safety cell. Conversely, in the event that the door is forcedopen during a road accident, the passenger safety cell strength isseverely compromised, thus possibly endangering the passengers anddriver of the vehicle.

An impact occurring during a crash can deform the vehicle door, and thenormal release mechanism of the latch is inadvertently operated, thusreleasing the door.

An object of the present invention is to provide a door latch which isless likely to unlatch during a crash.

Thus, in one form of the invention, a latch arrangement includes a latchand a release mechanism operable such that when the latch in an unlockedlatched first condition, an initial operation of the release mechanismchanges a state of the latch to a latched second condition that isdifferent from the first condition. A subsequent operation of therelease mechanism unlatches the latch. The actuator according to thepresent invention can be used to lock the latch.

It is also known to have latches which are power openable, that it themechanism that opens the latch can be driven by an actuator, such as anelectric motor.

The signal to operate the power actuator is generated by an initialmovement of an outside door handle associated with the latch/poweractuator. Since the initial movement of the outside door handle simplyoperates a signalling switch, the force required to lift the outsidedoor handle during this initial movement is very low.

However, if the power actuator malfunctions, further movement of theoutside door handle causes mechanical components of the door latch tomove and release the latch. Thus, the force required to lift the doorhandle during this subsequent movement is considerably more than theforce required to lift the door handle during the initial movement.

There is an ongoing requirement for vehicles to have reduced noiselevels, and in particular reduce wind noise levels. Reduced wind noiselevels can be achieved by increasing the seal load acting between thedoor and the adjacent door aperture of the vehicle. However, an increasein seal load also requires an increase in the force required to unlatchthe latch.

It is difficult to control the tolerances on seal loads between variousdoors of a vehicle, and therefore the force required to unlatch thelatch on different doors of the same vehicle varies significantly. Assuch, during power opening of a door latch, different doors of the samevehicle may take different times to open.

In particular, where a power actuator takes a significantly longer timethan usual to open the associated door, the person lifting the doorhandle may well have moved the door handle from the initial positioninto the manually opening phase of the door handle.

As such, a person opening different doors of the same vehicle can berequired to input significantly different forces into each door handle.

An object of a preferred embodiment of the present invention is toalleviate this problem. Thus, according to the present invention, thelatch arrangement is preferably further operable by a power actuator.

When providing a power openable door latch which requires an initial andsubsequent operation of a release mechanism, the initial operation canbe chosen to move only a certain number of components of the latch. Inparticular, the tolerances on these particular components can be tightlycontrolled. Furthermore, the force required to move these components canbe relatively low. Thus, the force required to fully actuate an outsidedoor handle on the first occasion can remain low. Furthermore, thisforce is consistent when compared with other door handles of the samevehicle.

The time taken to manually fully lift an outside door handle isconsiderably longer than the time required for the power actuator tounlatch the latch. Thus, under normal circumstances when the latch isbeing power unlatched, the door will open sometime when the outside doorhandle is being lifted, even though the lifting the outside door handleis not acting to unlatch the latch. It is therefore easier to achieve aconsistent “feel” to all latches on a particular vehicle.

Preferably, the latch has a locked condition such that any number ofoperations of the release mechanism does not unlatch the latch when inthe locked condition. Preferably, the latch arrangement includes a latchbolt releasably retainable in a closed position by a first pawl.

Preferably, the first pawl is operable by a pawl lifter, and the pawllifter is moveable relative to the pawl from a first relative positioncorresponding at least to the unlocked latched first condition to asecond relative position corresponding at least to the latched secondcondition.

Preferably, the pawl lifter is moveable relative to the first pawl byvirtue of a lost motion connection between the pawl lifter and the firstpawl. Preferably, the lost motion connection is in the form of aprojection on one of the pawl lifter and first pawl that engages a slotin the other of the pawl lifter and first pawl. Preferably, one of thepawl lifter and first pawl is pivotally mounted. Preferably, both arepivotally mounted, and more preferably, both are pivotally mounted aboutthe same axis.

Preferably, the pawl lifter is biased to the first relative position.Preferably, the pawl lifter is retainable in the second relativeposition by a second pawl.

Preferably, with the first pawl in the released position, the secondpawl is not capable of retaining the pawl lifter in the second relativeposition. Preferably, with the latch bolt in the open position, thelatch bolt engages the first pawl to keep the first pawl substantiallyin the released position.

Preferably, the first pawl includes an abutment engageable with thesecond pawl such that the abutment engages the second pawl to move thesecond pawl to the released position with the first pawl in the releasedposition.

Preferably, the release mechanism includes a ratchet mechanism having afirst ratchet tooth and a second ratchet tooth to change a state of thelatch between the unlocked latched first condition and the latchedsecond condition and between the latched second condition and theunlatched condition upon respective engagement with a ratchet abutment.

Preferably, the ratchet teeth and the ratchet abutment are insubstantially permanent operable engagement. Preferably, the ratchetteeth and the ratchet abutment are capable of being maintained in adisengaged position to lock the latch. Preferably, one of the firstratchet teeth and the second ratchet teeth and the ratchet abutment aremounted on a ratchet lever. Preferably, the ratchet abutment is mountedon the ratchet lever, and the ratchet teeth are mounted on the pawllifter. Preferably, the ratchet lever is pivotally mounted on a releaselever. Preferably, the release lever is pivotally mounted on a chassisof the latch. Preferably, the ratchet lever is pivotally connected at afirst link pivot to a link, and the link constrains the first link pivotto move about an arc when the latch is locked.

Preferably, the link is pivotally mounted on a lock link at a secondlink pivot. Preferably, the lock link can be retained in a lockableposition to lock the latch. Preferably, with the latch in an unlockedcondition, the lock link can be moved to the lockable position by returnmovement of the release mechanism. Preferably, the lock link is moved tothe lockable position by return movement of the release lever.

Preferably, the latch arrangement is further operable by a poweractuator. Preferably, the power actuator is connected on a first pawltransmission path side of the ratchet mechanism. Preferably, the poweractuator is connected on a first pawl transmission path side of aconnection between the pawl lifter and the first pawl. Preferably, therelease mechanism is connected to an outside door handle.

FIGS. 21 to 25 sequentially show the sequence of events required tomanually release the latch in the event of failure of the powerunlatching actuator. FIGS. 21 to 25 show a latch arrangement 510including a latch 512 and a release mechanism 514. The latch 512includes a pivotally mounted latch bolt in the form of claw 516. Theclaw 516 can move between a closed position (as shown in FIG. 21)whereupon the claw 516 retains a striker 518 and an open position (asshown in FIGS. 25, 26 and 28) wherein the striker 518 is released, thusallowing the door to open. The claw 516 can also be retained in a “firstsafety” position (not shown), whereupon the associated door cannot beopened, but nevertheless is not fully shut.

The latch 512 further includes a first pawl 520 pivotally mounted to achassis 513 (shown schematically) of the latch 512 at a pivot B. Thefirst pawl 520 includes a pawl abutment 522 for engagement with a clawabutment 524 or a claw first safety abutment 526. The claw 516 includesa claw release abutment 527, and the pawl abutment 524 rests on an end527A of the claw release abutment 527 when the claw 516 is in the openposition (FIGS. 25, 26 and 28). The claw release abutment 527 ispositioned at a radius R1 which is greater than a radius R2 of the clawabutment 524 and the first safety abutment 526. Thus, with the latch 512in a closed position or a first safety position, the claw abutment 524sits at radius R2 relative to an axis A, which is closer to the axis Athan when the pawl abutment rests on the claw release abutment 527 whenthe latch 512 is in the open position. The pawl 520 is generally planarand sits below the pawl lifter 528 when viewing FIG. 21. The pawl lifter528 is also generally planarand pivotally mounted at a pivot B. The pawllifter 528 includes a first ratchet tooth 532, a second ratchet tooth534, and an abutment 536.

A second pawl 538 is pivotally mounted at a pivot C to the chassis 513of the latch 512. The second pawl 538 can be engaged with an end 536A ofthe abutment 536, as shown in FIGS. 23 and 24, and can be disengagedfrom the end 536A, as shown in FIGS. 21, 22 and 25, as will be furtherdescribed below. An outside release lever 540 is connected to an outsiderelease handle (not shown) at an end 542. The outside release lever 540is pivotally attached to the chassis 513 of the latch 512 at a pivot D.The outside release lever 540 includes a projection 544.

A ratchet lever 546 is pivotally mounted at a pivot E (situated betweenthe pivot D and the end 542). The ratchet lever 546 includes a ratchetabutment 548 that is remote from the pivot E.

A first link pivot F is situated between the ratchet abutment 548 andthe pivot E, which pivotally connects the link 550 with the ratchetlever 546. The end of the link 550 remote from the first link pivot F ispivotally mounted at second link pivot G to end 552A of the lock link552. The lock link 552 is pivotally mounted at a pivot H to the chassis513 of the latch 512. The end 552B of the lock link 552 includes a lockabutment 554. The lock link 552 further includes a return abutment 556between the pivot H and the end 552A.

The lock toggle 58 is pivotally mounted at a pivot J to the chassis 513of the latch 512 and includes a toggle abutment 560. The lock toggle 558forms the toggle part of an actuator 558A according to the presentinvention, only shown in FIG. 27 for clarity. The actuator 558A furtherincludes an electromagnetic coil assembly 558B, a core 558C and a frame558D. One end of the frame 558D is connected to the core 558C. Operationof the actuator 558A to move the lock toggle 558 between the positionshown in FIG. 27 and the position shown in, for example, FIG. 2, issubstantially as hereinbefore described with reference to the previouslymentioned actuators.

The lock link 552, the outside release lever 540, the pawl lifter 528and the first pawl 520 are all biased in a counter-clockwise directionby an appropriate bias mechanism, such as springs (not shown). The claw516 and the second pawl 538 are both biased in a clockwise direction byan appropriate bias mechanism, such as springs (not shown). The movementof the link 550 and the ratchet lever 546 is controlled by thecombination of the lock link 552, the outside release lever 540 and thepawl lifter 528. Hence, the link 550 and the ratchet lever 546 are notrequired to be biased either clockwise or counter-clockwise. The locktoggle 558 can be moved between positions shown in FIGS. 21 and 27 by anactuator (not shown).

An actuator 564 (shown schematically on FIG. 26 only) is connected tothe first pawl 520 and can be actuated to rotate the first pawl 520 in aclockwise direction to release the latch 512.

Note that in further embodiments, the actuator 564 could be connected tothe pawl lifter 528 (as shown in dashed line in FIG. 26) to rotate thepawl lifter 528, and hence the first pawl 520, in a clockwise directionto release the latch 572.

In the event of failure of the actuator 564, operation of the latcharrangement is as follows. Consideration of FIG. 21 shows the latch 512in a latched condition where the pawl abutment 522 engages the clawabutment 524 to retain the claw 516 in the closed position.

A comparison of FIGS. 21 and 27 shows that all components are in anidentical position, except for the toggle lock 558. As shown in FIG. 21,the toggle lock 558 has been pivoted counter-clockwise such that thelock abutment 554 does not align with the toggle abutment 560. As shownin FIG. 27, the lock toggle 558 has been pivoted clockwise such that thelock abutment 554 is aligned with the toggle abutment 560. FIG. 27 showsthe latch arrangement in a locked condition, and FIG. 21 shows the latcharrangement in an unlocked condition. However, it should be noted that,as shown in FIG. 21, the lock link 552 is nevertheless in a lockableposition since the toggle lock 558 can be pivoted clockwise. This can becontrasted with the position of the lock link 552, as shown in FIGS. 22and 23, where it is not in a lockable position since the lock toggle 558cannot be pivoted clockwise.

The projection 544 of the outside release lever 540 engages the returnabutment 556 of lock link 552. This engagement causes the lock link 552to be positioned as shown in FIG. 21, i.e., clockwise when compared withthe position of the lock link 552, as shown in FIG. 22.

In FIG. 22, the outside release lever 540 has been pivoted clockwiseabout the pivot D through an angle K and moves the projection 544clockwise about the pivot D in the general direction of an arrow X. Thisin turn has allowed the lock link 552 to pivot counter-clockwise, movingthe link 550 generally to the right when viewing FIG. 22.

This in turn has caused the ratchet lever 546 to pivot clockwise aboutthe pivot E, such that the ratchet abutment 548 is substantially engagedbehind the first ratchet tooth 532. At this stage, the pawl lifter 528and the first pawl 520 remain in the same position in FIG. 22 whencompared with FIG. 21.

FIG. 23 shows the outside release lever 540 having been moved to thefully actuated position. The lock link 552 remains in the same positionwhen comparing FIGS. 22 and 23. However, the ratchet lever 546 has beenmoved generally upwards, and the engagement between the ratchet abutment548 and the first ratchet tooth 532 has caused the pawl lifter 528 topivot clockwise when compared with FIG. 22. This clockwise rotation ofthe pawl lifter 528 allows the abutment 538A of the second pawl 538 toslide past the edge 536B of the abutment 536 and engage the end 536A ofabutment 536, thus preventing the pawl lifter 528 from rotatingcounter-clockwise about the pivot B.

Furthermore, the pawl lifter abutment 562 has approached the arm 520A ofthe first pawl 520, but as shown in FIG. 23, has not yet moved the arm520A. The pawl lifter 528 is moveable relative to the first pawl 520 byvirtue of a lost motion connection between the pawl lifter 528 and thefirst pawl 520. In a further embodiment, the lost motion connection canbe in the form of a projection on one of the pawl lifter 528 and thefirst pawl 520 engaging in a slot in the other of the pawl lifter 528and the first pawl 520.

The first actuation of the outside release lever 540 has moved thecomponents 540, 552, 550, 546, 528 and 538. However, as shown in FIG.23, the latch, i.e., the claw 516 and the first pawl 520, remain unmovedand in the same position as shown in FIGS. 1 and 2.

FIG. 24 shows the outside release lever 540 having been released andreturned to the position as shown in FIG. 21. This in turn has alsomoved the components 552, 550 and 546 to the position shown in FIG. 21.However, the pawl lifter 528 remains in the position as shown in FIG. 23by virtue of the second pawl 538. In particular, as shown in FIG. 24,the second ratchet tooth 534 is now presented in substantially the sameposition as the first ratchet tooth 532, as shown in FIG. 21.

Thus, a subsequent actuation of the outside release lever 540 causes theratchet abutment 548 to engage behind the second ratchet tooth 534 andfurther rotate the pawl lifter 528 to the position as shown in FIG. 25.However, in this case the pawl lifter abutment 562 causes the arm 520Ato rotate clockwise about the pivot B, thus releasing the pawl abutment522 from the claw abutment 524 and allowing the claw 516 to rotateclockwise to the open position.

FIG. 25 shows that the second pawl 538 has been disengaged from the pawllifter abutment 536 of the pawl lifter 528. This is due to an abutment(not shown) on the first pawl 520 being moved (as the first pawl 520rotates) to engage with the second pawl 538 and hence rotating thesecond pawl 538 counter-clockwise against the second pawl bias spring.

Thus, upon release of the outside release lever 540, the pawl lifterabutment 536 can bypass the abutment 538A of the second pawl 538 toachieve the position shown in FIG. 28.

With the actuator 564 operating correctly, operation of the latcharrangement is as follows. The latch 512 starts from the position asshown in FIG. 21. An initial operation of the outside door handlemanually moves the latch components to the position as shown in FIG. 22.At this stage, a sensing device, such as a switch, is triggered whichinstructs the actuator to rotate the first pawl 520 in a clockwisedirection. However, the power actuator does not act instantaneously andtakes a finite amount of time to rotate the first pawl 520. Thus, thecontinued lifting of the outside door handle might typically positionthe latch components somewhere between the position as shown in FIG. 22and FIG. 23 prior to the latch being power unlatched. Under thesecircumstances, clearly no subsequent manual operation of the outsidedoor handle is required, and the latch might typically move from theposition shown in FIG. 23 to the position shown in FIG. 26. Release ofthe outside door handle will then move the latch components to theposition shown in FIG. 28.

Operation of the latch arrangement when in the locked position shown inFIG. 27 is as follows. As mentioned above, the toggle lock 558 has beenrotated clockwise such that lock abutment 554 engages the toggleabutment 560. This prevents the lock link 552 from rotatingcounter-clockwise, and hence the second link pivot G remains fixedrelative to the chassis 513. Thus, the first link pivot F is constrainedto move about an arc centered at the second link pivot G. Thus, when theoutside release lever 540 is actuated, the ratchet abutment 548 movessubstantially upwardly when viewing FIG. 27 and bypasses the firstratchet tooth 532 without engaging it. Hence, the actuation of theoutside release lever does not move the pawl lifter 528, and the latch512 remains latched.

In a further embodiment, the actuator 564 does not need to be present.Thus, the latch 512 can only be opened manually and two actuations ofthe outside door handle will be required to open the latch.

Preferably, this arrangement has safety benefits in the event of a sideimpact on the vehicle. Thus, while a side impact on the vehicle door maydeform the door such that the latch components move from the positionshown in FIG. 21 through the position shown in FIG. 22 to the positionshown in FIG. 23, under such circumstances the door does not open. Thiscan be contrasted with known door latches wherein a single pull of theoutside door handle opens the door. Such knows latches therefore run therisk that a single side impact to the door will also move the latchcomponents to their unlatched position and hence allow the door to open.

FIG. 31 shows a further latch arrangement 610, similar to the latcharrangement 510, with components that fulfill substantially the samefunction labelled 100 greater. FIG. 31 shows the latch arrangement 610in a latched condition, similar to the condition of the latcharrangement 510 shown in FIG. 21. In this case, the only differencebetween the latch arrangement 610 and the latch arrangement 510 is thatlatch arrangement 610 does not include a lock toggle 558. Thus, thelatch arrangement 610 can be power unlatched or manually unlatched (whenits power actuator fails) in a similar manner to latch arrangement 510.However, the latch arrangement 610 cannot be locked.

The latch arrangement 610 is in an unlocked latched first condition asshown in FIG. 31 by virtue of the fact that the latch arrangement 610cannot be locked.

In a further embodiment, the actuator associated with the latcharrangement 610 can be deleted to provide a non power operable latcharrangement which cannot be locked. In a further embodiment of a nonlockable latch, the lock link 652 and the link 650 of the latcharrangement 610 can be deleted and replaced by a bias member, such as aspring, which lightly biases the ratchet lever 546 in a clockwisedirection to ensure engagement of the ratchet abutment 648 withappropriate ratchet teeth 632 and 634.

In this embodiment, the ratchet teeth 632 and 634 and the ratchetabutment 648 are in substantially permanent operable engagement, andhence the latch arrangement 610 cannot be locked by virtue ofdisengagement of the ratchet teeth 632 and 634 and the ratchet abutment648. Though in yet further embodiments, the latch arrangement 610 couldalternatively be locked by virtue of a block mechanism or a free wheeltype mechanism positioned somewhere in the transmission path between theoutside door handle and the first pawl 620.

FIGS. 32 to 38 show a further embodiment of a latch arrangement 710wherein features which perform substantially the same function as in thelatch arrangement 510 have been labelled 200 greater. Only the toggle758 of the actuator according to the present invention has been shownfor clarity. The pivots 2E, 2D and 2H as shown in FIG. 33A are thefunctional equivalents of the pivots E, D and H of the latch arrangement510.

FIG. 40 shows that the lock link 652 is pivotally mounted at the pivot2H, which is coincident with the pivot 2D about which the outsiderelease lever 740 pivots. Furthermore, a pin 767 on the ratchet lever746 projects between a slot formed by guides 768 of the lock link 752.The pin and slot arrangement replaces the link 550 of the latcharrangement 510.

Although a preferred embodiment of this invention has been disclosed, aworker of ordinary skill in this art would recognize that certainmodifications would come within the scope of this invention. For thatreason, the following claims should be studied to determine the truescope and content of this invention.

1. An actuator comprising: a magnetic field generator: and anelectromagnetic coil arrangement moveable relative to the magnetic fieldgenerator, to define a first position of the actuator and a secondposition of the actuator, wherein, when the actuator in in the firstposition, a pulse of current through the electro magnetic coilarrangement produces a region of magnetic field that repels the magneticfield generator from the first position of the actuator and attracts themagnetic field generator towards the second position of the actuator tomove the actuator to the second position.
 2. The actuator as defined inclaim 1, wherein the magnetic field generator is a single permanentmagnet.
 3. The actuator as defined in claim 1, wherein the magneticfield generator is a an electromagnetic coil.
 4. The actuator as definedin claim 1, wherein the pulse of current moves the magnetic fieldgenerator.
 5. The actuator as defined in claim 1, wherein the pulse ofcurrent moves the electromagnetic coil arrangement. 6-7. (canceled) 8.The actuator as defined in claim 1, wherein the electromagnetic coilarrangement includes a frame having a free end and a magnetic corehaving core ends and a side, and the frame is connected to one of thecore ends of the magnetic core and extends along the side of themagnetic core, and the free end of the frame is spaced from the other ofthe core ends to provide the region of magnetic field. 9-12. (canceled)13. The actuator as defined in claim 1, wherein the electromagnetic coilarrangement includes an end, and the region of magnetic field is locatedat the end of the electromagnetic coil arrangement.
 14. The actuator asdefined in claim 13, wherein the electromagnetic coil arrangementincludes a central region and an outer region, and the region ofmagnetic field is located between the central region and the outerregion.
 15. The actuator as defined in claim 14, wherein the region ofmagnetitic field is positioned over a limited circumferential extent ofthe electromagnetic coil arrangement.
 16. The actuator as defined inclaim 1, wherein a first air gap is provided between the electromagneticcoil arrangement and the magnetic field generator when the actuator isin the first position and a second air gap is provided between theelectromagnetic coil arrangement and the magnetic field generator whenthe actuator is in the second position, wherein a size of the first airgap is greater than 1 mm.
 17. (canceled)
 18. The actuator as defined inclaim 16, wherein a size of the second air gap is greater than 0.5 mm.19-22. (canceled)
 23. The actuator as defined in claim 1, wherein themagnetic field generator comprises a first magnetic field generator anda second magnetic field generator in spaced apart relationship, and theelectromagnetic coil arrangement is situated between the first magneticfield generator and the second magnetic field generator.
 24. Theactuator as defined in claim 23, wherein the first magnetic fieldgenerator and the second magnetic field generator are mounted on anon-magnetic frame, wherein the first magnetic field generator, thesecond magnetic field generator and the non-magnetic frame move duringactuation of the actuator.
 25. (canceled)
 26. The actuator as defined inany claim 1, wherein the actuator provides security functions on avehicle. 27-32. (canceled)
 33. The actuator as defined in any claim 42,wherein the latch includes a latch housing, and the actuator ispositioned in the latch housing of the latch. 34-38. (canceled)
 39. Theactuator as defined in claim 4, wherein the magnetic field generator isa single permanent magnet having a single pole, the electromagnetic coilarrangement includes a frame, and the region of magnetic field includesa north pole and a south pole, wherein one of the north pole and thesouth pole repels the single pole of the magnetic field generator fromthe first position of the actuator and the other of the north pole andthe south pole attracts the single pole of the magnetic field generatortowards the second position to move the actuator to the second position.40. The actuator as defined in claim 1, wherein a first air gap isprovided between the electromagnetic coil arrangement and the magneticfield generator when the actuator is in the first position and a secondair gap is provided between the electromagnetic coil arrangement and themagnetic field generator when the actuator is in the second position,wherein a size of the first air gap is less than 4 mm.
 41. The actuatoras defined in claim 40, wherein a size of the second air gap is lessthan 4 mm.
 42. The actuator as defined in claim 26, wherein the actuatorperforms one of the following functions: providing a lock/unlockfunction by blocking/unblocking a transmission path between a handle anda latch, providing a free wheel locking function in the transmissionpath between the handle and the latch, providing a superlocked function,providing a child safety function, releasing the latch, and latching thelatch.
 43. The actuator as defined in claim 26, wherein the actuatorperforms one of the following functions: opening a fuel filler flap, andunlatching the fuel filler flap.
 44. A latch arrangement comprising: alatch; a release mechanism; a manually actuable element; and a controlmechanism including an actuator comprising: a magnetic field generator,and an electromagnetic coil arrangement movable relative to the magneticfield generator to define a first position of the actuator and a secondposition of the actuator, wherein, when the actuator is in the firstposition, a pulse of current through the electromagnetic coilarrangement produces a region of magnetic field that repels the magneticfield generator from the first position of the actuator and attracts themagnetic field generator towards the second position of the actuator tomove the actuator to the second position, wherein the actuator providesa security function on a vehicle, and the latch is operable toreleasably retain a striker in use, and a part of the release mechanismis retained in a rest position by the magnetic field generator toprovide for a lock condition.
 45. The latch arrangement as defined inclaim 44, wherein the magnetic field generator is a control pawl. 46.The latch arrangement as defined in claim 44, wherein the part of therelease mechanism is a lock/unlock lever.
 47. The latch arrangement asdefined in claim 45, wherein the control pawl is pivotally moveableabout a pivot axis and a center of gravity of the control pawl issubstantially located at the pivot axis.
 48. The latch arrangement asdefined in claim 44, wherein the magnetic field generator is moveablebetween the lock condition and an unlocked condition by manual operationof a coded security device.